Nickel-induced crystallization of amorphous silicon

J. A. SCHMIDT; N. BUDINI; P. RINALDI; R. D. ARCE; R.H. BUITRAGO

Puerto Iguazú

Congreso; Latinoamerican Simposium on Solid State Physics; 2008

Soc. Latinoamericana de Física

We use the nickel-induced crystallization of hydrogenated amorphous silicon (a- Si:H) to obtain large grained polycrystalline silicon thin films on glass substrates. We deposited a-Si:H by plasma enhanced chemical vapour deposition at 200 ºC, preparing intrinsic and slightly p-doped samples. Each sample was divided in several pieces, over which we sputtered increasing Ni concentrations. We compare two crystallization methods, namely conventional furnace annealing (CFA) and rapid thermal annealing (RTA). The crystallization was followed by optical microscopy and scanning electron microscopy observations, X-ray diffraction, and reflectance measurements in the UV region. The large grain sizes obtained – larger than 100 μm for the samples crystallized by CFA – are very encouraging for the preparation of low-cost thin film polycrystalline silicon solar cells.